2-
7
Spark
plug
Improper gap between
electrodes
Weak or no spark
Engine fails or is hard to start. Engine
lacks power. Unstable idle speed
Adjust by slightly bend the side electrode till the gap
is 0.8-0.9 mm
Electrodes are jointed by
carbon deposit
Weak or no spark
Engine fails to start.
Remove carbon deposit from electrodes
Too much carbon deposit
or over-oiled dirt around
the spark plug
Weak or no spark
Engine fails or is hard to start. Engine
lacks power. Unstable idle speed
Clear away carbon deposit or oiled dirt
Spark plug is damaged
Weak or no spark
Engine fails or is hard to start. Engine
lacks power. Unstable idle speed
Replace the damaged spark plug with a new one of
the same type
Loose park plug
Air leakage between
spark
and
cylinder
head
Engine is hard to start. Unstable idle
speed
Tighten up spark plug
Camshaft
assembly
Excessive wear for cam
Air intake and exhaust
is not smooth
Engine lacks power. Too much noise
from valve train.
Replace the cam
Excessive wear for timing
driven sprocket hole
Too much clearance
between hole and shaft
Abnormal
sound
from
camshaft
assembly
Replace the timing driven sprocket
Excessive
wear
for
camshaft
Too much clearance
between hole and shaft
Abnormal
sound
from
camshaft
assembly
Replace the camshaft and shaft sleeve
Thermostat
Thermostat is damaged or
plug is loose
Poor rejection of heat
Engine overheats
Replace the thermostat or tighten up the plug